A:Types of aquatic animals include marine mammals such as whales, dolphins, sea lions, seals, manatees and walruses. Other types are fish, including bony fish such as groupers and cartilaginous fish such as sharks and rays. Invertebrate aquatic animals include sponges, corals, sea stars, sea anemones, sea urchins and sea cucumbers. Other examples include sand dollars, jellyfish and colony animals such as the Portuguese man-of-war, marine worms, clams, mussels and barnacles.

A:The 42 known species of dolphins live in the waters of oceans and rivers all over the world. Dolphins are found everywhere, from shallow coastal waters to the deep of the open ocean, and they migrate to and from certain areas due to water temperature and food availability.

A:Whales and dolphins beach themselves, or end up beached, for reasons ranging from injury and illness to polluted water and simply becoming stranded at low tide. When these creatures travel in pods, the entire pod is likely to end up beached if the leader accidentally strands itself on shore, explains Mental Floss.

A:There are numerous endangered species in the ocean, many of which are whales and turtles. Some notable examples are the blue whale, sperm whale, Kemp's ridley turtle and hawksbill turtle. There are also some plants listed as endangered ocean species.

A:Crayfish use their gills to breathe. A crayfish has a gill at the base of each leg. These gills are very delicate and are covered by the crayfish's carapace, or shield. This carapace is aligned backwards from the head, allowing water to run through in a channel over the gills, which provides a continuous source of oxygen that allows the crayfish to breathe.

A:Most sea sponges are detrivorous, meaning they consume organic debris and various microbes that drift through ocean currents. Harp sponges, however, are carnivorous and use hooks located on their arms to catch shrimp and other small animals.

A:The flesh of the barracuda sometimes carries the toxin ciguatera, although it is regularly eaten by humans. Symptoms of ciguatera poisoning include nausea, vomiting and diarrhea. Neurological symptoms, such as headaches, paresthesia and vertigo, often follow. Scarce treatment options exist for ciguatera poisoning, although recovery is possible in time.

A:A Green Turtle is an endangered, herbivore reptile. It can be found in tropical and sub tropical habitats. Its name derives from the green color of its skin and not the color of its shell, which is usually brown or olive. On average, it lives to be over 80 years old in the wild. Also, it can grow up to 5 feet long and weigh up to 700 pounds.

A:The biggest recorded lobster ever caught weighed 44 pounds, 6 ounces and was caught in 1977. According to the Guinness Book of World Records, it was taken from the waters off the coast of Nova Scotia, and it measured 3 feet 5 inches from the tip of its largest claw to the end of its tail fan.

A:Dolphins use echolocation for communicating with one another and for locating objects in their surrounding environments. Regardless of whether dolphins use echolocation for social purposes, such as communication, or for finding and avoiding obstacles, the mechanism of echolocation uses the same techniques. Dolphins generate beams or waves of clicking sounds, then pause to wait for a response, either from another dolphin or from an object.

A:Coral is a colorless marine animal that lives on the ocean floor and can be red, orange and other colors. Any color that appears to be present on coral is a buildup of algae that live on the coral. Like other animals of the sea, coral can change color with emotion.

A:Angler fish, Pacific Viperfish, Wolfish, Goblin Shark and Sloane's Viperfish are just a few of the terrifying fish lurking in the ocean's depths. Once you move past the point where light reaches, the world's oceans turn into a terrifying place filled with strange creatures.

A:Most commonly, the seashell is associated with love and fertility, but the meaning ascribed to seashells differs depending on the source and type of seashell. For example, medieval Christian tradition associates the seashell with pilgrims. Artists and art movements, such as practitioners of Feng Shui, also have different interpretations of the symbolism of seashells.

A:Crayfish, which are freshwater crustaceans closely related to lobsters, have large claws with which they threaten predators and protect themselves. In addition, when crayfish are frightened, they make menacing gestures with their claws, propel themselves backwards and use their tails to throw mud at their enemies.

A:Dwarf crayfish usually grow to 1.5 to 2 inches in length. In the wild, they are brown or gray with brown or blue tints, but a selectively bred bright-orange variety is popular in the aquarium market. Dwarf crayfish thrive in small tanks by themselves or in large tanks with other fish. They are omnivores and eat a variety of plant and animal life.

A:A baby whale is called a calf, its mother is a cow and its father is a bull. Because whales are mammals, they give birth to their live babies and nurse them in infancy. A calf lives in the mother's uterus during gestation and is fed through an umbilical cord. Most whales give birth to a single calf at a time, but several instances have been recorded in which twin calves have been born in the wild.

A:According to Discovery of Sound in the Sea, animals use sound to communicate underwater. They emit different types of sounds and gather information on their surroundings by the echoes from those sounds, a process called echolocation.

A:Birds of prey, sharks, large fish, eels and crocodiles are predators of the sea snake. Sea snakes live in shallow waters and breathe air using a long lung that also assists in buoyancy. Although the sea snake isn't aggressive, it produces some of the deadliest venom in the world.

A:When you put a seashell to your ear you are not hearing the ocean, you are hearing the ambient noise coming from inside your ear and around you. The seashell captures and amplifies the noise, which resonates inside the shell and sounds like the rolling waves of the ocean. This effect is called seashell resonance.

A:Found in Arctic waters, the narwhal is related to the bottlenose dolphin, beluga, porpoise and orca. It is easily distinguishable by the sword-like spiralling tusk that grows through the upper lip of the male. The male's tusk can grow up to 8.8 feet in length although the female grows a much smaller tusk. The narwhal grows anywhere between 13 to 20 feet and weighs up to 3500 pounds.